Now we have the idea of how the process works. Let's have a look at the second section single note melody and how to harmonize it with basic chords.

In this second section the tonality changes to E major. First we have an E7 (I), moving to an A7 (IV), moving back to the E7 (I), finally winding up on a B7 (V7). This is clearly a "Blues" tune! It uses dominant 7ths chords on all the chords, it has a I-IV-V progression, it's rhythmic pulse is implied eighth note triplet swing. If it looks and sounds like a "Blues", then it is a "Blues"!